Pinhole leaks in copper tubing leave experts scratching their heads Copper has been successfully used for water supply piping for more than 70 years, and is perceived as the industry standard. Consumer confidence in copper is high, and the material has an earned reputation for quality. Copper tubing failure is rare. But corroding copper tubing has recently been reported in cities as far apart as Phoenix, Ariz. and Andover, Mass. Other cities reporting problems with pinhole leaks in copper include Saugus, Calif., Lima, Ohio, and Jacksonville, Fla. In Jacksonville, the problems were so serious that the city, in an unprecedented step, banned the use of copper for residential water supply piping. In